(1) Field of the Invention
The present invention relates to a structure for mounting a battery onto an electric vehicle.
(2) Description of Related Art
Structures for mounting batteries onto electric vehicles have been known in the art. The following related document 1 discloses an example of such a structure.
In the related document 1, as shown in FIGS. 1-4, a battery box (30) is fixed to side frames (20a and 20b) by front fixing portions (56a) and rear fixing portions (56b).    [Related Document 1] Japanese Laid-Open Publication H05-193369
However, by the technique of the related document 1, it is difficult to keep the battery box (30) in the correct position if a electric vehicle (10) is crashed.
For example, if a front end of the electric vehicle (10) is subject to impact, the battery box (30) moves forward due to inertia. Particularly, as the battery box (30) contains heavy batteries, the kinetic energy of the battery box (30) is considerable.
It is very difficult to keep the battery box (30) in the correct position by such a technique disclosed in the related document 1 whereby the front fixing portions (56a) and rear fixing portions (56b) fix the battery box (30) to the side frames (20a and 20b). Further, if the battery box (30) is fixed to the side frames (20a and 20b) by the structure shown in the related document 1, it is necessary to increase the size of the front and rear fixing portions (56a and 56b), and consequently, the weight and costs increase.